TERRESTRIAL MOLERSCA INHABITING SOCIETY ISLANDS. 
27 
Dr. Pfeiffer, on the authority of Mr. Tucker, cites “ Tahiti ” as its habitat. I am 
confident it does not occur on that island. 
It is a thin, depressed, acutely cariuated species, of a luteous or whitish horn-color, 
with a dorsal and basal brownish red line ; the upper one traversing the middle of the 
volutions, and the lower one submarginal. The whorls are depressed or slightly 
convex and striated by rather rough lines of growth. The faint sutural line is 
narrowly margined. The convex base is considerably excavated on the boundaries of 
the umbilicus, which latter varies from moderate to large, conical and freely exposing 
all the volutions. The very oblique aperture is depressed, subsecuriform. Peristome 
thin and nearly straight, above the keel, beneath which it gently recedes, and presents 
a slight curve to the axis of the shell. They vary some in the elevation of the spire, 
and occasionally the lineations are obsolete. My largest examples are 1(5 mill, in the 
greatest dianuker. 
The animal, as seen through the thin shell, is maculated with dark slate and light 
gray. The exposed parts are slender and of a light gray or slate-color with a grayi.sh 
buff creeping-disk. The eye-peduncles are long and slender, darker generally than 
the other parts. The tentacles are very small, and the foot, Avhich equals in length 
the major diameter of the shell, is laterally grooved. 
Pease’s Helix lenia, which gradually merges into the typical Sivainsonii, is brownish 
horn-color, with or without a submedian obscure chestnut band, and usually has the 
whorls more convex and the last one narrower than in the type. It is closely allied 
to T. ahrochroa, Crosse, inhabiting the Viti Isles. 
T. AssiMiLis, Garrett. Plate III, fig. 44. 
Shell umbilicated, rather solid, .subpellucid, subtrochiform, strite fine and oblique; 
greenish horn-color, with two brownish red revolving narrow bands, one above nearly 
median, the other on the base and intermarginal ; spire variable, more or less depre.ssly 
conoid, rounded above ; suture with a narrow pale margin ; whorls 5^-6, the up|K'r 
ones convex, the three lower subplanulate, narrow, slowly and regularly increasing, 
the last one acutely carinated, the carina compressed, rugose; base subplanulate, 
umbilicus moderate, profound, with rounded margins ; aperture diagonal, depressed, 
securiform ; peristome thin, straight, above rectilinear, beneath the keel gently arched ; 
columella and base incrassated. 
Major diam. 15, height 7 mill. 
Hah. — Huaheine. 
This species is restricted to the above island, where it is not infrc'qucnt on the 
trunks of trees. 
It has hitherto been confounded with trochifm'mis and Eurydice, the latter a Tonga 
species. It is more nearly related to p<dlens than any other species ; but appears to 
me sufficiently distinct to rank as a separate species. Tliey are very uniform in color 
